The present invention relates to a outer dimensions and contact surfaces meet the international standard ISO 7816/2.
The term "check cards" when used in the following will refer to cards having at least one semiconductor chip embedded therein. Such cards are known in diverse embodiments; they are intended to communicate with terminal units, such as money dispensers, vending machines, card telephones, access control units and the like, whereby the circuit integrated in the semiconductor chip is activated via electric contacts located in the terminal unit. Since terminal units from different manufacturers should be compatible with cards from different manufacturers, both the outer dimensions of such a check card and the size and position of the contact surfaces relative to the outer edges of such a check card have been standardized. The outer dimensions of the card are international standardized by the standard ISO 7810, and the size and position of the contact surfaces of the semiconductor chip by the standard ISO 7816/2.
When a check card is inserted into a terminal unit, stop means located in the device bring the outer edges of the card into a certain position in which the contacts on the unit side are in contact with the contact surfaces of the card. The contacting is only successful if the position of the contacts is within the tolerance window defined by the standard.
Such a card meeting the international standard ISO 7816/2 will be referred to in the following as a "standard card."
The check cards are normally punched out of multicopy sheets or strips, the punching dies being aligned with markings which in turn have a certain predefined position relative to the contact surfaces. Afterwards the outer edges of the punched cards Must be positioned relative to the contact surfaces in such a way that the tolerance window defined by the standard for the contact surfaces is within the actually existing contact surfaces.
The precision of the punching dies used is coordinated with the available ranges of tolerance, so that it is not possible, for example, to repunch a standard card, once it is punched, using a reference edge of this card. In such a case the necessarily occurring positioning errors would overlap, in the most unfavorable case, and result in a value outside the acceptable extent of tolerance. A need therefore exists for an exact positioning of a multicopy sheet, strip or prepunched card starting out from the contact surfaces, or for detection of the actual position of the contact surfaces relative to a predetermined tolerance window. This localization or positioning should be performed by a device of simple and compact construction that works reliably and is easy to operate.
This problem is solved by a test head which works on the principle of galvanically scanning the limits or outer edges of the tolerance windows defined by the standard. The current flow is measured between a contact pin disposed in the middle of the tolerance window, for example, and contact pins disposed at the edge of the tolerance window defined by the standard.
Under certain conditions it may suffice to measure only one contact surface and to deduce the correct position of the other contact surfaces from the correct position of this contact surface. However, embodiments are preferred in which a plurality of contact surfaces are measured simultaneously in order to rule out angle offset errors. In the contact surface plan according to the standard ISO 7816/2 contacts C6 and C8 are preferably measured.
The test head has the advantage of being simple and robust, in particular compared with known optical localizing systems.
The test head can therefore be used particularly advantageously for the quality control of standard cards, i.e. for detecting the position of the contact surfaces of standard cards with respect to their agreement with the tolerance window defined by the standard. However, the test head can also be used for positioning cards or carriers having embedded semiconductor chips for processing, in particular punching. This problem arises particularly during the production of check cards that are very much smaller than the check cards whose outer dimensions meet the standard ISO 7810.
Current rapid developments in the relevant field, in particular the miniaturization of the terminal units, make it necessary to use check cards that are very much smaller than the standard cards customary up to now. In particular for mobile telephones, the so-called "mini chip card" has become accepted which is substantially smaller than a check card with international standardization of its outer dimensions, but whose contact surface plan meets that of the standard card.
In the current introductory phase of mini chip cards, the production means, and especially the personalization means, for check cards having embedded semiconductor chips are invariably oriented toward the standard format of ISO 7810, so that the substantially smaller mini chip cards cannot be personalized by conventional means. The various terminal units on the market furthermore require a stock keeping both of standard cards and of mini chip cards.
To solve these problems it would be advantageous if one could start out with a standard card and punch the mini chip card out of the standard card as the last production step. However, this is difficult because the mini chip card would have to be punched out using the outer edges of the standard card as reference edges. The outer edges of standard cards are already within a certain range of tolerance with respect to the position of the contact surfaces, so that in the most unfavorable case the punching tolerances would add up.